This application requests support for the purchase of a Hewlett Packard 5987A gas chromatography mass spectrometer system (GC/MS). This instrument will form the core of a new GC/MS facility which will be available to the faculty of the College of Physicians and Surgeons. No such facility currently exists on this campus. The GC/MS will initially be used to study a wide range of problems including: arachidonic acid metabolism to leukotrienes and prostaglandins, carbohydrate structure in human choriogonadotropins, identification of novel sulfate, esterified steroids, neonatal toxicology of halogenated aromatics, and the metabolism of cardiac anti-arrhythmic drugs. The research programs are advanced by groups of established investigators from 7 departments of the University and are supported by over 30 peer-reviewed NIH grants. The addition of a GC/MS will greatly extend the research capabilities of these and other investigators at this institution. Access to the GC/MS facility by investigators will be guaranteed by an Advisory Committee reporting to the Dean. The equipment will be maintained by trained professional and technical personnel and will be availabale 24 hours/day to a broad user group. Space for the shared GC/MS facility will be provided by the Department of Medicine; installation costs will be covered by Columbia University.